Full Wave Bridge Rectifier

A Simple 4A Full Wave
Bridge Rectifier

January, 2012

This PCB design is of a fused,
full-wave bridge
rectifier. It is useful for projects which will run off of
typical household line voltages (e.g. 230V/115V-AC). It is a very
simple PCB design that requires only 4 components; a diode bridge, 2
capacitors and a fuse.

Keeping a few of these built-up in the
lab keeps me from having to breadboard or wire-wrap them up when
needed. They are super cheap and easy to build. Whip one up and slap
it in.

The specs are largely dicated by the
rectifier you choose. In this case I am using a Vishay
GBL005 Glass Passivated Single-Phase Bridge Rectifier.

Absolute Maximum Ratings (TA
= 25 ºC)

VRRM =
50V

VRMS =
35V

VDC =
50V

IF = 3A
(PCB only), 4A with heatsink.

Typically I use them with a Radio
Shack 12.6V CT 3.0A Chassis-Mount Transformer Part #273-1511.
This transformer is able to convert 115VAC on it's primary to
12.6VRMS. With this transformer the two yellow leads are
the secondary windings providing 12.6VRMS. I just cap off
the black center tap wire. This gives me about 17.3 VDC on the
rectifier's output.

Remember that the secondary voltage on
the transformer is a nominal 12.6VRMS. I haveactually
measured this to be about 14.8 VRMS which gives 20.9 VPP
(VRMS x 1.414). A voltage drop of 2 diodes (VF
= 1 V) yields 18.9 VPP, with some capcitor smoothing of
the remaining 1.5V, pretty close to the 17.3 VDC measured.

Keep in mind that this is NOT a
regulated DC output. It is only full-wave rectified, meaning it is
not smooth. I use these where I might later replace it with a battery
or other DC power source where the intent is to feed it into some
sort of linear or switch-mode regulator.

You can put any size fuse you like (up
to a max of 4A) in the holder, but I typically use a 3A fuse such as
the Radio
Shack 270-1009 3-amp 250V ACG Glass Fuse. If you plan on drawing
more than 3A continuous you'll need to consider a suitable heatsink.